This invention relates to internal combustion engines and, more specifically, to improved port constructions for use in such engines.
Rotary, internal combustion engine housings must contain gases and, at the same time, provide geometrically accurate surfaces for the various seals to seal against. In typical engines, such as trochoidal engines, the housings are not structurally symmetrical nor are they loaded symmetrically in either the thermal or mechanical sense.
Ports in such engines which convey hot gases at high velocity pose a particular problem. Such ports typically will be exhaust ports, prechamber or swirl chamber ports. Deviations in geometry at such ports affect gas leakage, and thus engine efficiency, as well as seal life.
Heretofore, numerous attempts have been made to modify theoretical cold engine geometry such that when the engine heats up during operation, the geometry will assume a theoretically perfect shape to eliminate the problem. Such an approach is exemplified by U.S. Pat. No. 3,302,622.
In reciprocating engines employing valves, at exhaust ports, the high heat flux caused by hot gases passing therethrough have been known to cause thermal distortion of valve seats on the order of 0.15 mm. Again, gas leakage may occur, reducing engine efficiency and valve life will be shortened.